Reducing a data storage device boot time

ABSTRACT

A data storage device includes a data storage medium and a controller. The controller performs a boot-up sequence that includes operations that transition the data storage device from a lower operational state to a higher operational state in which the data storage device is ready to service host commands. The controller also carries out metadata updating operations independently of the boot-up sequence operations. Carrying out the metadata updating operations independently of the boot up sequence operations prevents the metadata updating operations from substantially contributing to a boot-up time.

BACKGROUND

Data storage devices are typically included in systems having one ormore host computers. Examples of data storage devices include hard diskdrives (HDDs), which are electromechanical devices containing spinningdisks and movable read/write heads, solid state drives (SSDs), which usememory chips and contain no moving parts, and hybrid drives, whichcombine features of HDDs and SSDs in one unit.

SUMMARY

In one embodiment, a data storage device is provided. The data storagedevice includes a data storage medium and a controller. The controllerperforms a boot-up sequence that includes operations that transition thedata storage device from a lower operational state to a higheroperational state in which the data storage device is ready to servicehost commands. The controller also carries out metadata updatingoperations independently of the boot-up sequence operations. Carryingout the metadata updating operations independently of the boot upsequence operations prevents the metadata updating operations fromsubstantially contributing to a boot-up time.

In another embodiment, a method is provided. The method includesperforming, in a data storage device, a boot-up sequence comprisingoperations that transition the data storage device from a loweroperational state to a higher operational state in which the datastorage device is ready to service host commands. The method alsoincludes carrying out metadata updating operations independently of theboot-up sequence operations. Carrying out the metadata updatingoperations independently of the boot up sequence operations prevents themetadata updating operations from substantially contributing to aboot-up time.

In yet another embodiment, a data storage device is provided. The datastorage device includes a data storage medium and a controller. Thecontroller performs a boot-up sequence that includes operations thattransition the data storage device from a lower operational state to ahigher operational state in which the data storage device is ready toservice host commands. The controller also carries out metadata updatingoperations independently of the boot-up sequence operations and duringan idle time of the data storage device.

This summary is not intended to describe each disclosed embodiment orevery implementation of the data storage device boot time reductiontechnique described herein. Many other novel advantages, features, andrelationships will become apparent as this description proceeds. Thefigures and the description that follow more particularly exemplifyillustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an example apparatus having a data storagedevice in accordance with one embodiment.

FIG. 2 is a flow diagram of a method of reducing a data storage deviceboot time in accordance with one embodiment.

FIGS. 3A and 3B illustrate a comparison of metadata managementoperations carried out in first and second disc drives.

FIG. 4 is a block diagram of a hard disc drive that employs a method ofreducing boot time in accordance with one embodiment.

FIG. 5 is an isometric view of a solid-state drive that employs a methodof reducing boot time in accordance with one embodiment.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Embodiments of the disclosure generally relate to reducing boot time indata storage devices.

Computers typically include data storage devices (e.g., hard disc drives(HDDs), solid state drives (SDDs), hybrid drives, etc.). Generally, botha computer and a data storage device included in the computer have alower operational state (e.g., an “off” state) and a higher operationalstate (e.g., an “on” state or an active state). When transitioning fromthe lower operational state to the higher operational state the computerand the data storage device are booted. Booting the computer and thedata storage device includes executing low-level code (e.g., boot code)to configure components of the computer and the data storage device foroperation and control by higher-level software, such as firmware,operating system, or applications. This typically involves performing asequence of operations that are referred to herein as boot up sequenceoperations. Reducing boot time is desirable to enhance an end userexperience.

When a data storage device (e.g., a HDD) is initially installed in ahost computer, the data storage device may have a relatively smallamount of metadata (e.g., a relatively small logical to physical mappingtable). However, over time, data storage devices accumulate largeamounts of metadata that enable efficient data management and therebyhelp with data storage device performance. This is especially true inshingled magnetic recording (SMR) data storage devices, which utilizedynamic logical block address (LBA) mapping schemes (e.g., media cache)and journaling that employ large amounts of metadata. Currently, a datastorage device boot-up sequence includes metadata updating operations,which can contribute substantially to the boot time.

Embodiments of the disclosure reduce boot time in data storage devicesby decoupling metadata updating operations from other boot-up sequenceoperations, and performing the metadata updating operationsindependently of the boot-up sequence operations. An example of a datastorage device in which metadata updating operations may be decoupledfrom other boot-up operations is described below in connection with FIG.1.

It should be noted that the same reference numerals are used indifferent figures for same or similar elements. It should also beunderstood that the terminology used herein is for the purpose ofdescribing embodiments, and the terminology is not intended to belimiting. Unless indicated otherwise, ordinal numbers (e.g., first,second, third, etc.) are used to distinguish or identify differentelements or steps in a group of elements or steps, and do not supply aserial or numerical limitation on the elements or steps of theembodiments thereof. For example, “first,” “second,” and “third”elements or steps need not necessarily appear in that order, and theembodiments thereof need not necessarily be limited to three elements orsteps. It should also be understood that, unless indicated otherwise,any labels such as “left,” “right,” “front,” “back,” “top,” “bottom,”“forward,” “reverse,” “clockwise,” “counter clockwise,” “up,” “down,” orother similar terms such as “upper,” “lower,” “aft,” “fore,” “vertical,”“horizontal,” “proximal,” “distal,” “intermediate” and the like are usedfor convenience and are not intended to imply, for example, anyparticular fixed location, orientation, or direction. Instead, suchlabels are used to reflect, for example, relative location, orientation,or directions. It should also be understood that the singular forms of“a,” “an,” and “the” include plural references unless the contextclearly dictates otherwise.

FIG. 1 is a block diagram of an example apparatus 100 that includes adata storage device 102 in accordance with one embodiment. Data storagedevice 102 includes a storage controller or control circuit 106 thatcommunicatively couples a storage tier 108 to a host 104 via a hostinterface 122. In an implementation, the storage tier 108 is a dynamicstorage tier. The storage controller 106 provides a mechanism to allowthe host 104 to store data to and retrieve data from the storage tier108. In an implementation, the storage tier 108 may be a main datastore. The storage tier 108 may include without limitation one or moreof magnetic data storage discs, optical data storage discs, non-volatilerandom access memory (RAM), such as NAND flash memory and a volatile RAMstorage medium such as dynamic random access memory (DRAM). The storagetier 108 may include a reserved area 109 in which metadata (e.g., one ormore logical to physical mapping tables) may be stored.

The storage controller 106 may utilize communication interfaces andprotocols including SATA (serial advanced technology attachment), SCSI(small computer system interface), eSATA (external serial advancedtechnology attachment), SAS (serial attached SCSI), USB (universalserial bus), and others to communicate with the host 104 via the hostinterface 122. The storage controller 106 also includes a metadatamanagement module 110 that carries out metadata loading, processing,synchronization, etc.

As can be seen in FIG. 1, the storage controller 106 also includes amemory 124 that may be used for storing data and/or one or more modulessuch as 110 in some embodiments. It should be noted that, in differentembodiments, module 110 may comprise hardware, software and/or firmware.In one embodiment, the memory 124 may serve as a system memory intowhich metadata such as logical to physical mapping tables are stored. Inother embodiments, a separate memory or memory section 127 may serve asthe system memory into which metadata such as logical to physicalmapping tables are stored. In one embodiment, the system memory (e.g.,124 or 127) may include a DRAM. The storage controller 106 furtherincludes a processor/control circuit 128. The processor 128 may performfunctions of the storage controller 106 including functions disclosedherein as performed by module 110. The processor 128 may executeinstructions stored on non-transitory computer readable media to performthe functions of the storage controller 106.

In one embodiment, module 110 may include multiple sub-modules. Thesub-modules may include a metadata loading module 112, a journalingmodule 114 and a metadata updating module 116. Metadata loading module112 is capable of loading a copy of metadata from reserved area 109 intoeither memory 124 or memory 127. Journaling module 114 managesjournaling information (e.g., mapping information from host commandswhich, upon execution, result in changes to metadata (e.g., logical tophysical mapping changes)). Metadata updating module 116 is capable ofprocessing pending metadata updates from journaling module 114 andmodifying the metadata loaded by metadata loading module 112 accordingto the pending metadata updates. Metadata updating module 116 is alsocapable of storing updated metadata in reserved area 109. In oneembodiment, metadata updating module 116 updates a metadata master tablein reserved area 109.

Upon power-on reset of the data storage device 102 and before the datastorage device 102 is ready for host commands, metadata loading module112 loads a copy of metadata from reserved area 109 into either memory124 or memory 127. The loading of the metadata is carried out as part ofa boot up sequence in data storage device 102. However, in data storagedevice 102, metadata updates are decoupled from the boot-up path and arecarried out, for example, during an idle time or during a power modetransition (e.g., during a transition from a first power level fornormal operation of device 102 to a second reduced power level). Theupdates are carried out by metadata updating module 116 which, asindicated above, processes pending metadata updates from journalingmodule 114 and modifies the metadata loaded by metadata loading module112 according to the pending metadata updates. In certain applicationsthat have heavy loads (e.g., network-attached storage (NAS) webservers), there may be no idle time for metadata updates in data storagedevice 102. In such embodiments, a parallel task is set up to processthe metadata once a predetermined threshold (e.g., a predeterminednumber of pending metadata updates) is met. The parallel task may beexecuted by the main processor (e.g., processor 128) or by an auxiliaryprocessor. An optional auxiliary processor is denoted by referencenumeral 129 in FIG. 1.

FIG. 2 is a flowchart showing a metadata management method 200 carriedout in a data storage device (such as 102 of FIG. 1) in accordance withone embodiment. At block 202, data storage device power upinitialization is carried out. The device power up initialization mayinvolve performing a sequence of operations that help the data storagedevice transition from a lower operational state (e.g., an “off” state)to a higher operational state. If the data storage device is a HDDs or ahybrid drive, a disc spin up operation 204 may be a part of the power upinitialization. Also, for data storage devices such as HDDs, SSDs andhybrid drives, a copy of metadata from a reserved area (e.g., reservedarea 109 of FIG. 1) is loaded into a system memory (e.g., memory 124 ormemory 127 of FIG. 1). The metadata loading operation is denoted byreference numeral 206 in FIG. 2. At block 208, a determination is madeas to whether all the loaded metadata is current. This may involvedetermining whether there are any pending metadata updates in ajournaling system of the data storage device (e.g., journaling module114 of FIG. 1). If all the loaded metadata is current (e.g., there areno pending metadata updates in the journaling system), the data storagedevice is ready to service commands from a host (e.g., commands fromhost 104 of FIG. 1) as indicated by block 210. If at least some of theloaded metadata is not current (e.g., there are pending metadata updatesin the journaling system), control moves to block 212. At block 212, theloaded metadata is updated (e.g., by metadata updating module 116). Asindicated earlier, the updating of the metadata is decoupled from theloading of the metadata and therefore the updating of the metadata maybe carried out as a parallel task. Accordingly, when the metadataupdates are taking place at block 212, the data storage device iscapable is servicing host commands that are directed to data storagelocations whose associated metadata is current. When the update processis complete, the data storage device is ready to service host commandsthat are directed to any data storage locations in the data storagedevice.

During operation of the data storage device, changes to metadata arerecorded as journaling information. The loaded metadata at 206 is notcontinuously updated with the changes to the metadata. However, at block214, when a determination is made that the changes to the metadata havereached a predetermined threshold, the loaded metadata is updated withthe changes as a parallel task at block 216. If, at block 214, adetermination is made that the changes to the metadata have not reachedthe predetermined threshold, control passes to block 218. At block 218,a determination is made as to whether the data storage device is in anidle state. This may involve determining whether the data storage devicehas not received any host commands for a predetermined amount of time.If, at block 218, the data storage device is found to be in an idlestate, control passes to block 216 where the loaded metadata is updatedas a parallel task. If the data storage device is found not to be in anidle state, servicing of host commands continues as shown in block 220.

FIGS. 3A and 3B illustrate a comparison of metadata managementoperations carried out in first and second disc drives. FIG. 3A includesoperations 300A carried out in a first disc drive. Operation 302A is alast save/commit operation of an updated metadata master table to a datastorage disc. Operation 304A is a write operation that stores user datato a data storage disc. Operation 306A involves journaling of metadatachanges due to the write operation 304A. Operation 308A places the firstdisc drive in a power save mode. Operation 310A power cycles the firstdisc drive. Operation 312A is a disc spin up operation upon power up ofthe first disc drive. Operation 314A involves reading/loading themetadata master table. Operation 316A includes reading through ajournaling space for metadata changes and updating the read/loadedmetadata master table to reflect the metadata changes. This operation inthe first disc drive is carried out as part of the boot up sequence ofthe first disc drive (e.g., before the first disc drive is ready toservice host commands at 318A) and can cost about 50 milliseconds (ms)to about 500 ms depending on a size of the metadata that is changed. Aswill be described below in connection with FIG. 3B, to address themetadata update-related time delay in the boot up, metadata isprocessed/updated when the device in in an idle state.

FIG. 3B includes operations 300B carried out in a second disc drive inaccordance with one embodiment. Operation 302B is a save/commitoperation of an updated metadata master table to a data storage disc.Operation 304B is a write operation that stores user data to a datastorage disc. Operation 306B involves journaling of metadata changes dueto the write operation 304B. Operation 308B updates the metadata mastertable to reflect the metadata changes due to the write operation 304B.Operation 310B places the second disc drive in a power save mode.Operation 312B power cycles the second disc drive. Operation 314B is adisc spin up operation upon power up of the second disc drive. Operation316B involves reading/loading the saved metadata master table. Thesecond disc drive is ready to service host commands at 318B uponcompletion of the operation 316B. By pre-processing metadata at 308Bbefore the power cycle at 312B, operation 316A carried out during bootup on the first disc drive is eliminated from the boot up sequence ofthe second disc drive, thereby substantially reducing readying time ofthe second disc drive.

FIG. 4 shows a block diagram of a disc drive 400 that carries outmetadata management in accordance with one embodiment. Disc drive 400 isa particular example of a data storage or memory device 108. As will bedescribed in detail further below, in one embodiment, disc drive 400employs one or more discs on which multiple data tracks may be writtenin a partially-overlapping shingled pattern, with each successive trackoverwriting a portion of the previous track.

Disc drive 400 is shown in FIG. 4 to be operably connected to a hostcomputer 402 in which disc drive 400 may be mounted. Disc drive 400includes a microprocessor system 404 that generally provides top levelcommunication and control for disc drive 400 in conjunction withprogramming for microprocessor system 404 stored in microprocessormemory 406. Disc drive 400 may communicate with host computer 402 usinga bus 408.

Memory 406 can include RAM, read only memory ROM, and other sources ofresident memory for microprocessor 404. Disc drive 400 includes one ormore data storage discs 412. Discs 412 are rotated at a substantiallyconstant high speed by a spindle control circuit 414. One or more heads416 communicate with the surface(s) of discs 412 to carry out dataread/write operations. The radial position of heads 416 is controlledthrough the application of current to a coil in an actuator assembly417. A servo control system 420 provides such control.

As noted above, in some embodiments, tracks may be written on one ormore storage discs 412 in a partially-overlaying relationship. Theoverlaying of tracks is shown in close-up view of area 422 of disc(s)412. In area 422, a corner of head 416A is shown writing a track portion424. Different shading within the track portion 424 represents differentmagnetic orientations that correspond to different values of storedbinary data. The track portion 424 is overlaid over part of trackportion 425. Similarly, track portion 425 is overlaid over part ofportion 426, portion 426 is overlaid over portion 427, etc.

The portions 424-427 may be part of what is referred to herein as aphysical band which, in this embodiment, may include tens, hundreds orthousands of similarly overlapping, concentric portions 424-427. Gapsare created between such physical bands so that each physical band canbe updated independently of other physical bands. The overlaying ofsuccessive track portions within a physical band in shingled magneticrecording (SMR) means that individual parts of the physical band may notbe randomly updated on their own. This is because spacings betweencenters of track portions 424, 425, 426, 427, for example, are smallerthan a width of a write pole (not separately shown) of head 416.However, a width of a reader (not separately shown) of head 416 may besmall enough to read individual track portions 424, 425, 426, 427,thereby enabling random reads of data to be carried out.

In certain embodiments, disc drive 400 includes a memory 428 that mayserve as, for example, a first/upper level cache denoted by referencenumeral 428A. In some embodiments, memory 428 is physically separatefrom discs 412. The memory 428 may be of a different type than the discs412. For example, in certain embodiments, memory 428 may be constructedfrom solid-state components. In one embodiment, memory 428 may be aFlash memory or a DRAM.

In some embodiments, the one or more storage discs 412 are managed asnon-overlapping disc portion 430 and disc portion 435. In someembodiments, disc portion 430 is used for a second level cache denotedby reference numeral 430A and disc portion 435 serves as a main storedenoted by reference numeral 435A. In an alternate embodiment, each ofthe first level cache 428A, the second level cache 430A and the mainstore 435A may be allocated from a pool of memory locations thatincludes, for example, storage locations from memory 428 and storagelocations or physical bands from storage discs 412. Dashed box 427 ofFIG. 4A indicates that, in the alternate embodiment, the entire set ofstorage locations that constitutes the storage space supplied by disc(s)412 and memory 428 in disc drive 400 may be organized for three uses,namely the first level cache 428A, the second level cache 430A and mainstore 435A.

In the embodiment of FIG. 4, disc drive 400 may use memory 428 inconjunction with disc portion 430 in order to manage data as the data isbeing transferred to main storage locations 435 on disc(s) 412. In theinterest of simplification, components such as a read/write channelwhich encodes data and provides requisite write current signals to heads416 is not shown in FIG. 4. Also, any additional buffers that may beemployed to assist in data transfer to the memory 428 and the mainstorage locations 435 are not shown in the interest of simplification.

As noted above, SMR may be used for storage in disc portion 430, whichserves as second-level cache 430A. Also, as can be seen in FIG. 4A, mainstorage locations 435 are on a same data storage medium as thesecond-level cache locations 430. Thus, in the embodiment of FIG. 4A,second-level cache 430A is a media cache.

A SMR media cache such as 430A may rely on a high cleaning throughput toimprove the host write throughput. Accordingly, a large number ofextents (e.g., 2 million nodes per 1 TB of capacity) may be enabled,with each extent having a corresponding mapping element. The largenumber of mapping elements substantially increases metadata updates.

Accordingly, the embodiment of FIG. 4 employs a metadata loading module112, a journaling module 114 and a metadata updating module 116 in amanner described above, such that metadata loading operations aredecoupled from metadata updating operating operations, thereby reducingboot time. Metadata loading module 112, journaling module 114 andmetadata updating module 116 may be part of microprocessor system 404 ormay be separate components coupled to microprocessor system 404. Modules112, 114 and 116 operate in a manner described above in connection withFIG. 1 and carry out the metadata updates, for example, during and idletime of disc drive 400. Therefore, in the interest of brevity, adetailed description of modules 112, 114 and 116 is not repeated inconnection with FIG. 4. It should be noted that, in some embodiments, anauxiliary processor 405 may be employed to carry out metadata updates inparallel when microprocessor 404 is servicing host commands.

FIG. 5 illustrates an oblique view of a solid state drive (SSD) 500 inwhich the presently disclosed metadata management technique describedabove in connection with FIGS. 1 and 2 is useful. SSD 500 includes oneor more circuit card assemblies 502 and typically includes a protective,supportive housing 504, a top cover (not shown), and one or moreinterface connectors 506. SSD 500 further includes a controller ASIC508, one or more non-volatile memory devices 510, and power regulationcircuitry 512. The memory devices 510 are essentially the SSD's datastorage media for the caches and main store. In some applications, SSD500 further includes a power-backup energy storage device, such as asuper-capacitor 514.

In accordance with certain aspects, the solid-state drive 500 includes acircuit card assembly 502 that includes a connector 506 for connectionto a host computer. In accordance with certain aspects, the connector506 includes a NVMe (non-volatile memory express), SCSI, SAS, FC-AL(fiber channel arbitrated loop), PCI-E (peripheral componentinterconnect express), IDE (integrated drive electronics), AT (advancedtechnology), ATA (advanced technology attachment), SATA, IEEE (instituteof electrical and electronics engineers)-1394, USB or other interfaceconnector adapted for connection to a host.

If, as shown in FIG. 5, more than one non-volatile memory device 510 isincluded in SSD 500, then one of the non-volatile memory devices 510 maybe used as the first level cache. Physical storage locations (forexample, erasure blocks) in the other one or more non-volatile memorydevices 510 may be utilized as second level cache and as main storagelocations. In other embodiments, physical storage locations in the oneor more non-volatile memory devices 510 may serve a pool of physicalbands for assignment to first level cache, second level cache and mainstorage. In SSD 500, controller ASIC 508 may include a metadata loadingmodule 112, a journaling module 114 and a metadata updating module 116that operate in a manner described above.

In accordance with various embodiments, the methods described herein maybe implemented as one or more software programs running on one or morecomputer processors or controllers, such as those included in devices100, 400 and 500. Dedicated hardware implementations including, but notlimited to, application specific integrated circuits, programmable logicarrays and other hardware devices can likewise be constructed toimplement the methods described herein.

The illustrations of the embodiments described herein are intended toprovide a general understanding of the structure of the variousembodiments. The illustrations are not intended to serve as a completedescription of all of the elements and features of apparatus and systemsthat utilize the structures or methods described herein. Many otherembodiments may be apparent to those of skill in the art upon reviewingthe disclosure. Other embodiments may be utilized and derived from thedisclosure, such that structural and logical substitutions and changesmay be made without departing from the scope of the disclosure.Additionally, the illustrations are merely representational and may notbe drawn to scale. Certain proportions within the illustrations may beexaggerated, while other proportions may be reduced. Accordingly, thedisclosure and the figures are to be regarded as illustrative ratherthan restrictive.

One or more embodiments of the disclosure may be referred to herein,individually and/or collectively, by the term “invention” merely forconvenience and without intending to limit the scope of this applicationto any particular invention or inventive concept. Moreover, althoughspecific embodiments have been illustrated and described herein, itshould be appreciated that any subsequent arrangement designed toachieve the same or similar purpose may be substituted for the specificembodiments shown. This disclosure is intended to cover any and allsubsequent adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the description.

The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b) and is submitted with the understanding that it will not be usedto interpret or limit the scope or meaning of the claims. In addition,in the foregoing Detailed Description, various features may be groupedtogether or described in a single embodiment for the purpose ofstreamlining the disclosure. This disclosure is not to be interpreted asreflecting an intention that the claimed embodiments employ morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter may be directed toless than all of the features of any of the disclosed embodiments.

The above-disclosed subject matter is to be considered illustrative, andnot restrictive, and the appended claims are intended to cover all suchmodifications, enhancements, and other embodiments, which fall withinthe true spirit and scope of the present disclosure. Thus, to themaximum extent allowed by law, the scope of the present disclosure is tobe determined by the broadest permissible interpretation of thefollowing claims and their equivalents, and shall not be restricted orlimited by the foregoing detailed description.

1. A data storage device comprising: a data storage medium; and acontroller configured to: perform a boot-up sequence comprisingoperations that transition the data storage device from a loweroperational state to a higher operational state in which the datastorage device is ready to service host requests; and carry out metadataupdating operations in parallel with servicing host requests, therebypreventing the metadata updating operations from substantiallycontributing to current and future boot-up times.
 2. The data storagedevice of claim 1 and wherein the boot-up sequence of operationsperformed by the controller further comprises a metadata loadingoperation that is different from the metadata updating operations. 3.The data storage device of claim 1 and wherein the controller is furtherconfigured to carry out the metadata updating operations during a datastorage device idle time.
 4. The data storage device of claim 1 andwherein the controller is configured to carry out the metadata updatingoperations in parallel with servicing of the host requests when apredetermined threshold of pending metadata updates is reached.
 5. Thedata storage device of claim 1 and wherein the controller is configuredto carry out the metadata updating operations in parallel with theservicing of the host requests when the servicing of the host requestsare for data storage locations where associated metadata is current. 6.The data storage device of claim 1 and wherein the metadata updatingoperations are carried out in parallel with the servicing of the hostrequests by a same processor.
 7. The data storage device of claim 1 andwherein the servicing of the host requests are carried out by a firstprocessor and the metadata updating operations are carried out inparallel by a second processor.
 8. A method comprising: performing, in adata storage device, a boot-up sequence comprising operations thattransition the data storage device from a lower operational state to ahigher operational state in which the data storage device is ready toservice host requests; and preventing metadata updating operations fromsubstantially contributing to current and future boot-up times bycarrying out the metadata updating operations in parallel with servicinghost requests.
 9. The method of claim 8 and wherein performing theboot-up sequence of operations comprises performing a metadata loadingoperation that is different from the metadata updating operations. 10.The method of claim 8 and wherein preventing metadata updatingoperations from substantially contributing to current and future boot-uptimes further comprises carrying out the metadata updating operationsduring a data storage device idle time.
 11. The method of claim 8 andfurther comprising carrying out the metadata updating operations inparallel with the servicing of the host requests when a predeterminedthreshold of pending metadata updates is reached.
 12. The method ofclaim 8 and further comprising carrying out the metadata updatingoperations in parallel with servicing host requests when the servicingof the host requests are for data storage location locations whereassociated metadata is current.
 13. The method of claim 8 and whereinthe metadata updating operations are carried out in parallel with theservicing of the host requests by a same processor.
 14. The method ofclaim 8 and wherein the servicing of the host requests are carried outby a first processor and the metadata updating operations are carriedout in parallel by a second processor.
 15. A data storage devicecomprising: a data storage medium; and a controller configured to:perform a boot-up sequence comprising operations that transition thedata storage device from a lower operational state to a higheroperational state in which the data storage device is ready to servicehost requests; and carry out metadata updating operations in parallelwith servicing host requests and during an idle time of the data storagedevice.
 16. The data storage device of claim 15 and wherein the metadataupdating operations comprise updating a metadata master table stored onthe data storage medium.
 17. The data storage device of claim 15 andwherein the controller is further configured to load a copy of themetadata master table into a data storage device memory that is of adifferent memory type than the data storage medium, and wherein thecontroller is configured to perform the loading of the copy of themetadata master table into the data storage device memory as part of theboot-up sequence.
 18. The data storage device of claim 17 and whereinthe data storage device memory comprises a solid-state memory and thedata storage medium comprises a data storage disc.
 19. The data storagedevice of claim 15 and wherein the controller is further configured tocarry out the metadata updating operations in parallel with theservicing of the host requests when a predetermined threshold of pendingmetadata updates is reached.
 20. The data storage device of claim 15 andwherein the controller is further configured to carry out the metadataupdating operations in parallel with the servicing of the host requestswhen the servicing of the host requests are for data storage locationswhere associated metadata is current.